The election, which took place in May, was narrowly lost — by less than a percentage point — by far-right Freedom Party candidate Norbert Hofer.

The Freedom Party had challenged the election results, saying postal votes had been mishandled.

The term in office of the outgoing president, Heinz Fischer (independent), will end July 8. His duties as head of state will provisionally be fulfilled by Parliament President Doris Bures (Social Democrats) and her two deputies, Karlheinz Kopf and Hofer.

Back in May, the Interior Ministry had given Alexander van der Bellen (The Greens) 50.3% of the vote, compared with 49.7% for Hofer, who had run on an anti-immigration platform.

If elected, Hofer would be the first far-right head of state of a European Union country, though Austria's presidency is a ceremonial role. Nonetheless, Hofer had already said before the election that if he won, he would try to extend his limited powers.

During the investigation, 90 witnesses were called to clarify the allegations. Numerous election officials acknowledged in interviews that they had broken some laws when counting approximately 740,000 valid absentee ballots.

According to the Interior Ministry, many constituencies had started counting the absentee ballots on election night, when they were only legally allowed to do so the next day.

The court said in its ruling that it was using its strict standard on the application of election rules, as it said that might have influenced the results but added that there was no proof that the count had been manipulated, according to Reuters.